Hydraulic suspension system and method for operation of said system

ABSTRACT

Methods and systems for hydraulic vehicle suspension are provided. A hydraulic suspension system, in one example, includes a first manifold including a piston-side interface and a rod-side interface fluidically coupled to a piston chamber and a rod chamber, respectively, for each of a first hydraulic cylinder and a second hydraulic cylinder. In the system, the first manifold includes a first electrically activated valve fluidically coupled to the piston-side interfaces, a first damping device, and a second damping device, the first electrically activated valve is configured to lock and unlock vertical motion of the first and second hydraulic cylinders and, while vertical motion of the first and second hydraulic cylinders is locked, the first electrically activated valve permits fluidic communication between the first and second hydraulic cylinders to permit free roll motion in the hydraulic suspension system.

TECHNICAL FIELD

The present disclosure generally relates to a hydraulic suspensionsystem with a manifold and a method for operation of the hydraulicsuspension system.

BACKGROUND AND SUMMARY

Some vehicles utilize suspensions arrangements, such as independentfront suspension, to achieve various handling performancecharacteristics. Certain suspension systems utilize double-actinghydraulic cylinders capable of vehicle handling adjustment. In specificsystems, attempts have been made to use the double-acting cylinders forsuspension spring rate adjustment.

U.S. Pat. No. 7,059,127 B2 to Bauer discloses a hydro-pneumatic springsupport arrangement in an agricultural machine. The spring supportarrangement changes the device's spring rate during ballast adjustmentsto conform the spring rate to dynamic vehicle ballasting conditions.

The inventors have recognized several drawbacks with Bauer'shydro-pneumatic suspension system and other vehicle suspension systems.Bauer's system demands concurrent implementation of the vehiclesuspension spring rate and ballast adjustment. Furthermore, Bauer'ssystem may experience unwanted handling characteristics due to theomission of a control scheme intended to avoid undesirable overlappingkinematic modalities. Other vehicle hydraulic suspension systems haveattempted to deploy complex control circuity aimed at circumventingcertain handling characteristics. However, these systems may be complexand highly reliant on sophisticated electronic hardware which may becostly and, in the case of control circuit degradation, may beunreliable due to the diminished the capabilities of the control logic.

To overcome at least some of the aforementioned challenges, a hydraulicsuspension system is provided. The hydraulic system includes, in oneexample, a first manifold comprising piston-side interfaces and rod-sideinterfaces. The piston and rod side interfaces are fluidically coupledto a piston chamber and a rod chamber, respectively, in each of a firsthydraulic cylinder and a second hydraulic cylinder. In the system, themanifold includes a first electrically activated valve fluidicallycoupled to the piston-side interfaces of the first and second hydrauliccylinders. The manifold further includes a first damping device and asecond damping device. Further in the system, the first electricallyactivated valve is configured to lock and unlock vertical motion of thefirst and second hydraulic cylinders. In the system, while verticalmotion of the first and second hydraulic cylinders is locked, fluidiccommunication between the first and second hydraulic cylinders ispermitted via the first electrically activated valve to permit free rollmotion in the hydraulic suspension system. In this way, the firstelectrically activated valve arranged between the hydraulic cylindersand the damping devices allows suspension roll motion to occur whilevertical motion of both cylinders is locked. In this way, a conditionwhere both roll and vertical motion are locked, which may decreasehandling performance below a desired level, can be avoided, if wanted.

Further in one example, the hydraulic suspension system may furtherinclude a plurality of piloted check valves fluidically coupled to thepiston-side interfaces and the rod-side interfaces. In such an example,the plurality of piloted check valves may be fluidically coupled to aload sensing (LS) component via a second electrically activated valve.Arranging the piloted check valves in this manner allows suspension rollmotion to be locked and unlocked during desired periods of systemoperation. For instance, suspension roll motion may be permitted whilethe vertical motion of the first and second hydraulic cylinders islocked. Suspension roll motion may also be permitted when the system'sleveling function (e.g., cylinder position and/or pressure adjustment)is active. In this way, fluid may flow to both cylinders during levelingoperation. Consequently, the stiffness and position of the cylinders maybe more balanced in relation to one another which may enable the vehicleto achieve desired handling characteristics, if so desired.

It should be understood that the summary above is provided to introducein simplified form a selection of concepts that are further described inthe detailed description. It is not meant to identify key or essentialfeatures of the claimed subject matter, the scope of which is defineduniquely by the claims that follow the detailed description.Furthermore, the claimed subject matter is not limited toimplementations that solve any disadvantages noted above or in any partof this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic representation of a vehicle including a firstembodiment of a hydraulic suspension system with a first manifold and asecond manifold.

FIG. 2 shows a detailed view of the first manifold of the hydraulicsuspension system, depicted in FIG. 1 .

FIG. 3 shows a second embodiment of a hydraulic suspension system withmultiple manifolds.

FIG. 4 shows a method for operation of a hydraulic suspension system.

FIG. 5 shows a third embodiment of a hydraulic suspension system withmultiple manifolds.

FIG. 6 shows a table indicating use-case operating modes of the firstmanifold, depicted in FIG. 2 .

DETAILED DESCRIPTION

A hydraulic suspension system with a modular manifold is describedherein. The manifold allows the hydraulic suspension system to passivelyavoid unwanted system control variants, if desired. For example, thehydraulic suspension system may be designed to lock vertical motion oftwo hydraulic cylinders and may prevent a condition where one cylinderis locked while the other is unlocked. In this way, decreased handlingperformance caused by mismatched locking/unlocking conditions of the twohydraulic cylinders may be avoided. This vertical locking functionalitymay be achieved using a valve in fluidic communication with pistonchambers in both the hydraulic cylinders and multiple associated dampingdevices. Further, in one example, the hydraulic suspension system may bedesigned to prevent roll motion lock between two hydraulic cylinderswhile vertical motion of the hydraulic cylinders is locked. In this way,a solid lock condition in the system where both roll motion and verticalmotion are locked can be avoided, if wanted. Consequently, decreasedhandling performance stemming from the solid lock condition may beavoided.

The hydraulic system may be further designed to prevent roll motion lockwhile the system's leveling function (e.g., cylinder position and/orstiffness adjustment) is active. Further, in some embodiments,suspension roll motion may be designed to passively lock and allow thehydraulic cylinders to move independently. The passive locking featureof the hydraulic cylinders may enable the hydraulic suspension system toachieve desired higher speed handling characteristics. Theaforementioned roll motion features may be achieved via a plurality ofpiloted check valves arranged between the two hydraulic cylinders. Thepiloted check valves may close and open to lock and unlock roll motion,respectively. The piloted check valves may fluidically couple to asecond electrically activated valve which may fluidically couple to aload sensing (LS) line. Some aspects of suspension roll motion andvertical lock management may be passively deployed using the pilotedcheck valves in the system. Certain combinations of operational variantsmay therefore be passively enabled while others may be avoided to atleast partially satisfy system control goals using a smart hydrauliccircuit architecture. In this way, the suspension system may achievedesired control variants using an efficient hydraulic circuitarchitecture while decreasing the complexity of the system'sprogrammatic controls, if wanted.

FIG. 1 depicts a hydraulic suspension system in a vehicle with aleveling manifold and a manifold for axle roll motion and cylindervertical motion control. FIG. 2 shows a detailed illustration of a firstembodiment of the manifold designed with roll motion and vertical motionlock and unlock functionality. FIG. 3 depicts a second embodiment of amanifold with axle roll motion and vertical cylinder motion adjustmentfeatures. FIG. 4 shows a method for operation of a suspension system.FIG. 5 illustrates a third embodiment of a manifold for roll andvertical motion control. FIG. 6 shows a chart indicating an operationalmatrix related to suspension system roll and vertical motion locked andunlocked configurations.

FIG. 1 illustrates a vehicle 100 with a hydraulic suspension system 102.The vehicle 100 may, in one example, be an agricultural or industrialvehicle. In other examples, the vehicle may be a light, medium, or heavyduty commercial vehicle, passenger vehicle, and the like. Agriculturaland industrial vehicles may, in certain instances, experience widervariances in load and/or speed during use and therefore may beparticularly suited to leverage performance gains from the hydraulicsuspension system's kinematic adjustability described herein. However,other vehicles may similarly exhibit suspension performance gains andthe hydraulic suspension system therefore may have applicability acrossa wide variety of vehicle platforms to achieve targeted kinematiccharacteristics.

The hydraulic suspension system 102 may be designed with modularcomponent groups to facilitate an expansion of the hydraulic suspensionsystem's functionality and adaptability, if wanted. Consequently, thesuspension platform may be deployed in an even wider array of vehicles,which may further increase the platform's customer appeal.

The hydraulic suspension system 102 may include a leveling manifold 104.The hydraulic suspension system 102 may further include a manifold 106(e.g., central manifold) designed to manage suspension roll motion(e.g., axle roll motion) and/or hydraulic cylinder vertical lockingoperation. Suspension roll motion may be the side-to-side angularmovement of the suspension system and particularly the axle with regardto a horizontal axis or plane. The layout of the hydraulic componentsand specific structure and function of the manifold components iselaborated upon herein with regard to FIG. 2 .

The leveling manifold 104 may couple to the manifold 106 via an LS line108, line 110 (e.g., rod-side line), and a line 112 (e.g., piston-sideline). As described herein, the coupling between hydraulic lines,components, etc. may denote fluidic coupling between the componentswhere fluidic communication is established. The LS line 108 and theother load sensing conduits illustrated in FIG. 1 as well as FIGS. 2 and3 are designated via dotted lines. However, it will be understood thatthe LS lines and the other hydraulic lines described herein function asconduits for the system's working fluid. Further, as described herein aline may a hydraulic conduit which encloses a hydraulic fluid andprovides fluidic coupling between components to which it is attached.

The hydraulic suspension system 102 may further include a first dampingdevice 114, a second damping device 116, a third damping device 118,and/or a fourth damping device 120. As illustrated in FIG. 1 , potentialboundaries of the following devices: the leveling manifold 104; themanifold 106; and the damping devices 114, 116, 118, 120, are demarcatedvia twodash style lines. Thus, the twodash lines are themselves notdirectly indicative of hydraulic conduits. However, it will beappreciated that in other embodiments these devices may have differentcomponent groupings.

Each of the damping devices 114, 116, 118, 120 may be in fluidiccommunication with an accumulator 122 via lines 124. The accumulators122 may act as storage reservoirs and may include housings, interiorchambers, and the like. The first and second damping devices 114, 116may be in fluidic communication with an electrically activated valve 126in the manifold 106. The electrically activated valve 126 may bereferred to as a first electrically activated valve. The second andthird damping devices 118, 120 may be in fluidic communication with rodchambers 128, 130 in a first hydraulic cylinder 132 (e.g., a leftcylinder) and a second hydraulic cylinder 134 (e.g., a right cylinder),respectively. It will be appreciated that the first and second hydrauliccylinders may be associated with one of the vehicle axles (e.g., thefront vehicle axle). The damping devices may be configured to modulatevibrations of the hydraulic cylinders.

The first hydraulic cylinder 132 may further include a piston chamber136. The second hydraulic cylinder 134 may similarly include a pistonchamber 138. The first and second hydraulic cylinders 132, 134 may eachinclude a piston 140, a piston rod 142, a piston barrel 144, etc. whichallow for the system's height, stiffness, roll motion, and/or verticallock modes to be implemented. The hydraulic cylinders 132, 134 maytherefore take the form of double acting hydraulic cylinders. Thesystem's control modes are elaborated upon herein.

The piston chamber 136 may couple to the manifold 106 via line 146 andthe rod chamber 128 may couple to the manifold via line 148. Thus, themanifold 106 may include a first rod-side interface 147 and a firstpiston-side interface 149. Likewise, the piston chamber 138 may coupleto the manifold 106 via a line 150 and the rod chamber 130 may couple tothe manifold via a line 152. The manifold 106 may further include asecond rod-side interface 151 and a second piston-side interface 153. Asdescribed herein, the piston and rod side chambers may include cavities,walls, valving, and/or other piston and rod side components,respectively.

The first and second hydraulic cylinders 132, 134 may mechanicallycouple to a first vehicle component 154 (e.g., a vehicle axle) and asecond vehicle component 156 (e.g., a vehicle chassis). To elaborate,the first and second hydraulic cylinders 132, 134 may mechanicallycouple to the axle and the vehicle chassis at distinct locations (e.g.,at locations on laterally opposing sides of the vehicle). For instance,the first hydraulic cylinder 132 may mechanically couple to a firstsuspension arm or other suitable axle component and the second hydrauliccylinder 134 may mechanically couple to a second suspension arm or othersuitable axle shaft component. However, a variety of axle interfaceshave been envisioned. To elaborate, in one embodiment, the vehicle axlemay be included in an independent front suspension assembly 155. Theindependent front suspension assembly may include pivoting driveshaftsconnected via joints (e.g., universal joints) to allow opposing wheels157, 159 to independently articulate, under certain conditions. Theindependent front suspension assembly may comprise a differential and/orother conventional front suspension components.

In one embodiment, the vehicle axle may be a steerable axle, such as afront axle. In this way, the hydraulic suspension system may managevehicle steering characteristics. However, in other examples, the firstand second hydraulic cylinders 132, 134 may mechanically couple to arear axle. The relative position between the first and second vehiclecomponents may be referred to as the suspension's position (e.g., rideheight). A distance between the first vehicle component 154 and thesecond vehicle component 156, dictated by the hydraulic cylinders, isindicated at 158. During a position adjustment mode, this distance maybe lengthened or shortened to vary ride height. For instance, thecylinder's height may be adjusted taking into account vehicle weightdistribution. The variation in the system's ride height may bolstervarious aspects of vehicle operation such as handling, materialloading/unloading operation, and the like.

The leveling manifold 104, manifold 106, and the damping devices 114,116, 118, 120 may have a modular design, which enables the manifold tobe efficiently incorporated into a vehicle system. The modularity ofthese components may further allow for system reconfiguration and/orinclude additional modules intended to meet targeted end-use designgoals of a specific vehicle platform, if desired. In this way, thesuspension system's adaptability can be expanded, thereby increasingcustomer appeal.

The leveling manifold 104 may couple to a tank 160, a load sensing (LS)component 162 (e.g., compensator), and/or a pump 164 or other suitablepressure source. A tank line 166 may extend between the tank 160 and theleveling manifold 104 and provide fluidic connection there between. Aload sensing line 168 may extend between the LS component 162 and theleveling manifold 104 and a pump line 170 may extend between the pump164 and the leveling manifold. It will be appreciated that additionalcomponents may be positioned between the tank, LS component, and/or thepump and the leveling manifold, in other embodiments.

The tank 160 may function as a reservoir for the system's working fluid.The system's working fluid be a suitable hydraulic fluid such as oil(e.g., natural and/or synthetic oil). Thus, the tank 160 may include ahousing which encloses the system's working fluid. The pump 164 may bedesigned to deliver pressurized fluid to the leveling manifold 104. Forinstance, the pump may be a variable displacement pump (e.g., axialpiston pump). However, other suitable types have pumps have beencontemplated such as axial-flow pumps, centrifugal pumps, a pump with apressure vessel, etc. The LS component 162 may be coupled to the pump164. Thus, the LS component 162 and pump 164 may work in conjunction toadjust pump output based on the load sensing pressure. For instance, theLS component (e.g., pressure compensator) may constrain a higheroperating pressure (e.g., an upper operating pressure) by reducing pumpdisplacement (e.g., reducing pump displacement to a lower value such assubstantially zero) when the threshold pressure is reached. The LScomponent may therefore function as a pump control device. The levelingmanifold 104 may include a plurality of electrically activated valves.The valves may include a first valve 171, a second valve 172, a thirdvalve 173, and/or a fourth valve 174. The first valve 171 may be a3-way/2-position (3/2) valve with three hydraulic ports and twopositions. The third valve 173 may similarly be a 3/2 type valve. Thesecond valve 172 may be a 2/2 valve and the fourth valve 174 maysimilarly be a 2/2 style valve. However, other valves configurationshave been envisioned. The leveling manifold 104 may further include apressure compensator 175 designed to manage supply pressure in relationto load sensing. The leveling manifold 104 may further include a reliefvalve 176 bypassing the first and second valves 171, 172 and a reliefvalve 177 bypassing the third and fourth valves 173, 174.

The leveling manifold 104 may further include a plurality of orifices178 designed to manage and set leveling function speed. To elaborate,the orifices 178 may dictate the rate of suspension stiffness andposition adjustment. The orifice sizing may be tuned based on end-usetargets. The orifices may therefore include a housing with an interiorprofiled for flow restriction. The leveling manifold may further includea shuttle valve 179 which may allow the LS component 162 to see thehigher pressures in lines between the valves.

The vehicle 100 may further include a control system 180 with acontroller 182, actuators 184, and sensors 186. The controller 182 mayencompass the control device of the pump 164, discussed above. Thus, thecontroller 182 and more generally the control system 180 may encompassone or more physical devices that may be collocated and/or remotelylocated for implementing hydraulic system control strategies. Thecontroller 182 may receive signals from the sensors 186 positioned invarious locations in the suspension system 102 and vehicle 100. Thesensors may include pressure sensors 187 coupled to lines in theleveling manifold 104, a position sensor 188 coupled to the hydrauliccylinders 132, 134, a temperature sensor 189, a vehicle speed sensor190, a vehicle load sensor 191, and the like.

The controller 182 may send control signals to the actuators 184positioned at different locations in the suspension system 102 andvehicle 100. For instance, the controller 182 may send signals toactuators in the leveling manifold 104 such as actuators of componentsin the leveling manifold (e.g., valves 171, 172, 173, 174), actuators ofcomponents in manifold 106, actuators of components in the dampingdevice 114, 116, 118, 120 and the like. For example, the controller 182may send a control signal to an actuator in a valve to turn the valve onor off. Thus, the other controllable components in the suspension systemmay similarly function with regard to command signals and actuatoradjustment.

The controller 182 may include suitable circuitry for carrying out thesensing and control functionality such as memory 192 and a processor193, in one example. In such an example, of the controller 182 may holdinstructions stored therein that, when executed by the processor 193,cause the controller to perform the various methods, control techniques,etc. described herein. The processor 193 may include a microprocessorunit and/or other types of circuits. The memory 192 may include knowndata storage mediums such as random access memory, read only memory,keep alive memory, combinations thereof, etc. However, the controllermay include additional or alternative circuitry for carrying out thesensing and control strategies described herein.

The controller 182 may couple to an input device 194 (e.g., a consoleinstrument panel, a touch interface, a touch panel, a keyboard,combinations thereof, etc.). The input device 194, responsive to driverinput, may generate a request to adjust suspension stiffness and/orposition, trigger cylinder motion locking/unlocking, trigger suspensionroll motion locking/unlocking, etc. However, in other examples, theaforementioned control operations may be automatically adjusted based onvehicle operating conditions.

The control system 180 may operate the leveling manifold 104 indifferent modalities which enable the position and stiffness of thehydraulic cylinders 132, 134 to be independently adjusted. To elaborate,the leveling manifold 104 may, in a position adjustment mode, deliverfluid to the piston chambers of the hydraulic cylinders 132, 134 toextend the suspension (e.g., increase the height of the chassis (e.g.,front chassis) while substantially maintaining a pre-set target pressurein the rod chamber (slightly discharging rod chamber). Additionally, theleveling manifold may, in the position adjustment mode, discharge fluidfrom the piston chambers of the hydraulic cylinders in order to retractthe suspension itself (e.g., lowering-down the vehicle chassis), whilesubstantially maintaining a pre-set target pressure in the rod chamber(e.g., slightly pressurizing rod chamber). In a pressure adjustmentmode, the leveling manifold may pressurize the piston and rod chambersof the hydraulic cylinders to increase suspension stiffness withoutsubstantially changing axle position, if wanted. Further, in thepressure adjustment mode, the leveling manifold may discharge both thepiston and rod chambers of the hydraulic cylinders in order to reducesuspension stiffness without substantially changing axle position. Inthis way, the operational functionality of the suspension system isexpanded which enables the suspension system's degrees of freedom to becorrespondingly increased. The system's ride height and suspensionstiffness may therefore be granularly adjusted at separate times to moreaptly suit at least some the operating conditions experienced by thevehicle, if so desired. The control system may further be designed tocontrol suspension roll motion and vertical cylinder movement,elaborated upon herein.

An axis system 199 is provided in FIG. 1 as well as FIGS. 2, 3, and 5 ,for reference. The z-axis may be a vertical axis, the x-axis may be alateral axis (e.g., horizontal axis), and/or the y-axis may be alongitudinal axis, in one example. However, the axes may have otherorientations, in other examples.

FIG. 2 illustrates a detailed depiction of the manifold 106 (e.g.,central manifold), the damping devices 114, 116, 118, 120, and theaccumulators 122. The damping devices 114, 116, 118, 120 may beconfigured to manage proportional damping between a lower value (e.g.,minimum value) and a higher value (e.g., maximum value) based ontransient conditions. The lower value may occur when a proportionalvalve is closed (e.g., fully closed) and the higher value may occur whenthe proportional value is open (e.g., fully opened). In one example,damping may be increased (e.g., maximized) while the vehicle is brakingor accelerating to perform anti-dive/lift functions. Continuing withsuch an example, right and left damping may be managed independently, toincrease vehicle handling performance while cornering at high speed(e.g., maximizing damping on external cornering side valves). As such,in this example, the damping valve may be managed to improvelongitudinal and lateral vehicle dynamics. Consequently, the vehicle'shandling performance may be increased, thereby increasing customerappeal and satisfaction.

Each of the damping devices 114, 116, 118, 120 may have similarcomponents, in one embodiment. For instance, each of the damping devicesmay include an electrically activated valve 200 (e.g., proportionalvalve), a check valve 202 coupled in parallel with the electricallyactivated valve, a first orifice 204 positioned in a line 206, and/or asecond orifice 208 positioned in a line 210 arranged parallel to line212 and 206. However, other damping device arrangements have beenenvisioned. Further, in other embodiments, the configurations of thedamping devices may vary, which may increase system complexity.

The LS line 108, rod-side line 110, an piston-side line 112 connectingthe manifold 106 to the leveling manifold 104 shown in FIG. 1 , areagain illustrated in FIG. 2 . The damping devices 114, 116 are shownconnecting to the electrically activated valve 126 via lines 214, 216,respectively. The electrically activated valve 126 may be a 4/2 typevalve with four hydraulic ports and two positions. The four hydraulicports provide fluidic communication between the valve 126 and the firstdamping device 114, the second damping device 116, the piston chamber136, and the piston chamber 138. However, the valve 126 may have anothersuitable configuration, in other embodiments.

In an open position, the electrically activated valve 126 permits flowbetween the first damping device 114 and the piston chamber 136 via line218 and permits flow between the second damping device 116 and thepiston chamber 138 via line 220. However, in the open position of thevalve, cross flow between the piston chambers by way of the valve may beinhibited.

Conversely, in the closed position, the electrically activated valve 126may form a bridge connection (e.g., H-bridge connection) between thelines 218, 220. Thus, in the H-bridge connection example, a cross-overconduit extends between two lines connecting the piston chambers totheir respective dampers. The bridge connection allows the system toexhibit free roll movement in the suspension independent from aplurality of check valves in the manifold which enables a solid lockcondition (a condition where both vertical and roll motion in the systemis locked) to be avoided, if desired. Further, in the bridge connection,flow between the piston chamber 136 and first damping device 114 isrestricted. Further, in the bridge connection, flow between the pistonchamber 138 and second damping device 116 is restricted. To elaborate,sections of the H-bridge connection on the accumulator side of theconnection may be specifically restricted. The restrictions in thebridge connection in the valve 126 allow for pressure stabilization ofthe piston chambers 136, 138 after transients between the pistonchambers and a plurality of accumulators coupled to the first and seconddamping devices. As such, oscillatory motion in the system may beattenuated when the valve 126 is closed. The electrically activatedvalve 126 may be designed to close in response to energization and openin response to de-energization. In this way, the valve's openconfiguration may be a passive condition.

Opening the electrically activated valve 126 places the hydraulic systemin an unlocked state with regard to vertical motion of the cylinders. Inthe unlocked state, vertical suspension movement of the hydrauliccylinders 132, 134 is permitted. On the other hand, closing theelectrically activated valve 126 places the hydraulic system in lockedstate with regard to vertical motion of the cylinders. When the valve isdesigned to be open when de-energized, a suspension locking conditionmay be avoided when the valve exhibits degradation.

The first hydraulic cylinder 132 with the piston and rod chambers 136,128 and the second hydraulic cylinder 134 with the piston and rodchambers 128, 130 are illustrated in FIG. 2 . Lines 146, 148 connectedto the rod and piston chambers 128, 132 of the first hydraulic cylinder132 are further illustrated in FIG. 2 . Lines 150, 152 connected to thepiston and rod chambers 128, 130 of the second hydraulic cylinder 134are additionally shown in FIG. 2 . Each of the lines 146, 148, 150, 152may couple to a first piloted check valve 222, a second piloted checkvalve 224, a third piloted check valve 226, and a fourth piloted checkvalve 228, respectively. Pilot line 230 may couple the first check valve222 to the second check valve 224. Pilot line 232 may couple the thirdcheck valve 226 to the fourth check valve 228. Junctions 234 shown inFIG. 2 denote a fluidic junction between two lines facilitating fluidiccommunication between the lines. This junction notation is utilized inthe other figures described herein.

The manifold 106 may further include an electrically activated valve 236and an electrically activated valve 238. The electrically activatedvalve 236 may be a VNO type valve and the electrically activated 238 maybe a VCN type valve. However, other suitable valve types have beencontemplated. The electrically activated valve 236 may be referred to asa second electrically activated valve and the valve 238 may be referredto as a third electrically actuated valve or vice versa. It will furtherbe appreciated that the valves 236, 238 may be referred to as pilotingcontrol valves.

The manifold 106 may further include a first orifice 240 and/or a secondorifice 242 in a line 243. The manifold 106 may further include a thirdorifice 244 and a fourth orifice 246 residing in a line 247. Theorifices restrict flow through the line to which they are attached andmay include a housing with a flow restriction therein. The line 243 maybe arranged parallel to a line 248 in which the first and second pilotedcheck valves 222, 224 reside. Likewise, the line 247 may be arrangedparallel to a line 250 in which the third and the fourth piloted checkvalves 226, 228 reside. Positioning the orifices parallel to the pilotedcheck valves allows pressure stabilization between opposing (e.g., leftand right) cylinder piston chambers, thereby decreasing the chance ofthe variance in the cylinder pressures from exceeding a targeted level.To expound, placing the orifice in parallel with the piloted checkvalves provides pressure stabilization after roll transients, when rollmotion is locked, which prevents cylinder pressure variance fromsurpassing a desired level after several roll moments.

The architecture of the piloted check valves 222, 224, 226, 228 mayallow roll motion to be locked and unlocked when desired. To elaborate,when the piloted check valves 222, 224, 226, 228 are closed, suspensionroll motion may be locked. Conversely, while the piloted check valvesare opened suspension roll motion may be unlocked.

To manage piloted check valve status, the higher pressure between thepiston and rod chambers of the hydraulic cylinders 132, 134 may be usedto supply the hydraulic fluid to the piloting line via the electricallyactivated valve 238. Lines 250 couple the piloted check valves to theelectrically activated valve 238.

The manifold 106 may further include a shuttle valve 253 having lines252 extending between the valve and lines 248, 250. The shuttle valve253 may allow the valve 238 to see the higher pressure of the lines 248,250. However, in other embodiments the shuttle valve 253 may be omittedfrom the manifold 106. FIG. 5 shows an embodiment of a manifold 500 witha valve 502 (e.g., a 4/2 type valve), a valve 504, and a valve 506.These and other components in the manifold 500 may have structural andfunctional features similar to those described with regard to themanifold 106, shown in FIGS. 1-2 . Redundant description is thereforeomitted for brevity. The manifold 500 shown in FIG. 5 , however,replaces the shuttle valve with check valves 508 in lines 510 coupled tothe valve 506. This modification to the manifold 500 may allow for morerobust pressurization using line 512 during leveling operationindependent from operation of the valves 504, 506.

Returning to FIG. 2 , in one implementation, the electrically activatedvalve 238 may be closed when it is de-energized to enable the rollmotion to be passively locked. When the suspension roll motion ispassive locked, the first and second hydraulic cylinders 132, 134 maymove independently. The roll motion may be passively locked duringhigher speed vehicle operation to increase vehicle handling performance.The electrically activated valve 236 may be opened when it isde-energized such that the piloting lines are discharged via the LS line108 which may be connected to the tank 160 shown in FIG. 1 . To locksuspension roll motion both the valves 236, 238 may be energized via acommon command to pressurize the pilot lines 230, 232 of the checkvalves 222, 224, 226, 228.

To allow roll motion to be unlocked while leveling operation is active,the electrically activated valve 236 may be connected to the LS line 108which is routed to the leveling manifold 104, shown in FIG. 1 .Connecting the valve 236 to the LS line 108, allows the LS line topressurize the pilot lines 230, 232 for the check valves 222, 224, 226,228 when the leveling manifold is operational. Consequently, the pilotedcheck valves may be piloted open during leveling operation toconsistently deliver fluid to both hydraulic cylinders, independent fromthe control status of the electrically activated valves 236, 238, if sodesired. In this way, roll motion may be passively unlocked to achievedesired handling characteristics and potentially avoid a condition whereroll motion is unlocked while vertical motion is locked. To elaborate,when the leveling operation is active and the piloted check valves areunlocked, cylinder leveling may be balanced. Consequently, the systemmay achieve substantially symmetric leveling which may potentially avoida condition where one of the valves degrades and only one of thecylinders is allowed to move. In this way, vehicle handling performanceis increased. The orifice 240, 242, 244, 246 allow for the balancepressure between left and right cylinders after transients.Additionally, the orifices integrated into the valve 126 may provide arelatively slow pressure balance between the accumulator and piston whenvertical motion is locked, in some implementations.

Further, in one example, the line 108 connecting manifold 106 to theleveling manifold 104, depicted in FIG. 1 , may be used to discharge theworking fluid from the accumulators 122 during servicing, for instance.The control system may carry out accumulator discharge operation throughthe energization of the electrically activated valve 238 to open saidvalve. Further, during accumulator discharge operation, the controlsystem may turn off the other valves in the manifold 106 and/or theleveling manifold 104. With the valves in the manifolds in theaforementioned arrangement, the working fluid will flow from theaccumulators to the tank 160 through line 108 valve 171 and/or valve174, shown in FIG. 1 . Thus, the LS line 108 may serve as a drainpassage during servicing. In this way, the system's servicing and/orrepair efficiency may be increased.

Further, in an alternate embodiment, the valves 236, 238 may be replacedwith a 3/2 style valve but may retain the previously mentionedfunctionality of the valves 236, 238. However, using the two valves 236,238 (e.g., the 2/2 style valves) may reduce the likelihood of fluidleaks from line 108 potentially leading to decreasing the height of thesuspension.

FIG. 3 shows a second embodiment of a hydraulic suspension system 300which may include a leveling manifold 302, dampening devices 304, 306,308, accumulators 310, hydraulic cylinders 312, 314, tank 320, LScomponent 322, pump 324, and control system 326. The aforementionedcomponents may have a similar structure and function to thecorresponding components in the suspension system 102 shown in FIGS. 1and 2 .

The suspension system 300 may further include a manifold 316 with amodified arrangement. The suspension system 300, illustrated in FIG. 3 ,has one fewer rod-side damping device when compared to the suspensionsystem 102, depicted in FIGS. 1 and 2 . However, systems with fewer thanthree or greater than four damping devices have been contemplated. Twoof the piloted check valves coupled to the rod chambers of the hydrauliccylinders 312, 314 are omitted from the manifold 316, depicted in FIG. 3. In this way, fluidic communication between the rod chambers of thehydraulic cylinders may persist during the different modal controlstrategies. The suspension system 300 may achieve similar functionalitywith regard to the roll motion and vertical motion locking/unlockingfeatures in comparison to the suspension system 102, shown in FIGS. 1and 2 . For example, the suspension system 300, and specifically themanifold 316, may be configured to lock and unlock cylinder verticalmotion and axle roll motion. However, the suspension system 300 may havea slightly smaller range of actuator force controllability duringtransient conditions due to the reduced number of damping devices incomparison to the suspension system 102, depicted in FIGS. 1 and 2 .

Referring to FIG. 4 , a method 400 for operating a hydraulic suspensionsystem is shown. The method 400 may be implemented via one or more ofthe vehicle, hydraulic suspension systems, and system componentsdescribed above with regard to FIGS. 1-3 and/or 5 . However, in otherexamples, the method 400 may be implemented by other suitable vehicles,hydraulic suspension systems, and/or the system components. Furthermore,in one embodiment, the method 400 may be stored as instructions innon-transitory memory executable by a processor of a controller, such asthe controller 182 depicted in FIG. 1 . However, additional or alternatetypes of suitable control circuitry may be used, in other embodiments.

At 402, the method includes determining operating conditions. Theoperating conditions may include vehicle speed, vehicle load, ambienttemperature, suspension cylinder position, suspension cylinderstiffness, input device position, and the like. These conditions mayascertained from sensor signals and/or modeled.

At 404, the method determines whether to transition into a mode wherecylinder vertical motion is locked or to transition into a mode wherecylinder vertical motion is unlocked. Such a determination may take intoaccount system operating conditions, such as vehicle speed, vehicleload, operator activated input device configuration, etc. Specifically,in one example, the vehicle operator may lock and unlock vertical motionat their discretion and based on working conditions, for example.Additionally or alternatively, the controller may be designed to unlockvertical suspension movement when the vehicle travels above apredetermined speed, to increase the vehicle's handling performance. Forinstance, the vehicle operator may lock vertical suspension movementwhen they are connecting an accessory on the front hitch or are workingwith a front loader. Conversely, when the operator drives the vehicle ona road or field above a threshold speed (e.g., 5 km/h, 6 km/h, 10 km/h,etc.), vertical movement may be automatically unlocked to increase thevehicle's handling performance. As previously discussed, the design ofthe 4/2 type valve in the central manifold of the hydraulic systemallows (e.g., guarantees) roll motion to occur while vertical lock isenabled, to reduce the chance of the system exhibiting decreasedhandling performance.

If it is determined that neither mode transition is wanted, the methodmoves to 406. At 406, the method includes maintaining the suspensionsystem's current operating strategy. For instance, the system may besustained in a vertical lock or unlocked mode of operation.

However, if it is determined that a transition into the vertical lockmode is wanted, the method proceeds to 408. At 408, the method includestransitioning the suspension system into a vertical lock mode.Transitioning the system into the vertical lock mode includes at 410,closing the 4/2 type electrically activated valve in the manifold viavalve energization. In the closed position, the 4/2 valve a bridgeconnection permits fluid flow between the first piston chamber and thesecond piston chamber and restricts fluid flow to a first damping deviceand a second damping device from the first and second hydrauliccylinders. The bridge connection in the valve enables roll motionlocking to be inhibited while vertical locking is activated. In thisway, the vehicle may exhibit targeted handling characteristics.Although, the electrically activated valve in method 400 is described asa 4/2 style valve, other electrically activated valve configurationshave been envisioned.

If it is determined that a transition into the vertical unlock mode isdesired, the method proceeds to 412. At 412, the method includestransitioning into the vertical unlock mode. Transitioning into thevertical unlock mode includes at 414, opening the 4/2 electricallyactivated valve in the central manifold via de-energizing the valve. Inthe open position, fluid flow between the opposing piston chambers ofthe two hydraulic cylinders and associated accumulators is permittedwhile bridge-flow between the opposing piston chambers through the valveis inhibited. In this way, the system can exhibit vertical suspensionmovement. In the vertical unlock mode, suspension roll motion may belocked and unlocked based on vehicle operating conditions. For instance,roll motion may be unlocked during a leveling function. To elaborate,suspension roll motion may be unlocked responsive to locking verticalmotion of the first and second hydraulic cylinders through the operationof valves coupled to the piloted check valves in the central manifold.For example, electrically activated valves coupled to the piloted checkvalves (e.g., the valves 236 and 238 shown in FIG. 2 ) may be jointlyenergized to pilot open the check valves and permit suspension rollmotion. In one example, these electrically activated valves may beenergized via a common command signal. In this way, the system's commandlogic may be simplified. Conversely, the electrically activated valvescoupled to the piloted check valves may be de-energized to close thecheck valves and lock roll motion. In this way, suspension roll motionmay be locked and unlocked at advantageous times that allow the vehicleto achieve desired handling characteristics and avoid handlingcharacteristics that may diminish handling performance. The method mayfurther include, in one example, opening the electrically activatedvalve (e.g., the valve 238 shown in FIG. 2 ) coupled to the LS line(e.g., the line 108 shown in FIG. 2 ) while closing the other valves inthe system (e.g., valve 236, valve 126, and/or the valves in theleveling manifold) to discharge fluid from the accumulators. Aspreviously discussed, when the valves are in this arrangement,accumulator discharge operation may unfold during a servicing procedure,for example. Thus, the LS line may serve as a drain passage duringservicing. In this way, the system may be more efficiently serviced.

FIG. 6 depicts an exemplary chart 600 which correlates the roll andvertical motion operational variants in the hydraulic suspension system(e.g., hydraulic suspension system 102, shown in FIGS. 1-2 ) to oneanother in an operational mode matrix, in one embodiment. As describedherein exemplary does not denote any sort of preference but ratherindicates one of many possible facets of the systems and methodsdescribed herein. Row 602 indicates an operational configuration in thesystem where roll motion is permitted. When roll motion is permitted,the left and right hydraulic cylinders permit side-to-side angularmovement of the suspension system (e.g., axle). Row 604 indicates anoperational configuration in the system where roll motion is controlled.For instance, controlling roll motion may include substantiallyinhibiting roll motion or constraining roll motion with a desired range.Column 606 indicates an operational configuration of the system wherevertical motion is locked and column 608 indicates an operationalconfiguration of the system where the suspension is active (suspendedvertical motion (e.g., sprung and/or dampened motion) is allowed tooccur). As shown, when the system permits roll motion, vertical motionmay be locked or vertical suspension movement may be permitted. However,when roll motion is controlled, the system hydro-mechanically permits(e.g., guarantees) that locking of the system's vertical motion isinhibited. Thus, when roll motion is controlled vertical suspensionmovement may be solely allowed. In this way, conditions which maydegrade vehicle handling performance can be avoided.

The hydraulic suspension systems and methods described herein have thetechnical effect of reducing the likelihood (e.g., avoiding) ofdecreasing handling performance below a desired value via the avoidanceof a condition where one or the two hydraulic cylinders is locked whilethe other cylinder is unlocked. Another technical effect of the systemsand methods described herein is to enable suspension roll motion to beunlocked which allows fluid flow to both hydraulic cylinders when thesystem's leveling function is active. Flowing fluid to both cylindersallows for the stiffness and position of the cylinders to be morebalanced, if so desired, thereby increasing vehicle handlingperformance.

FIGS. 1-3 and 5 show example configurations with relative positioning ofthe various components. If shown directly contacting each other, ordirectly coupled, then such elements may be referred to as directlycontacting or directly coupled, respectively, at least in one example.Similarly, elements shown contiguous or adjacent to one another may becontiguous or adjacent to each other, respectively, at least in oneexample. As an example, components laying in face-sharing contact witheach other may be referred to as in face-sharing contact. As anotherexample, elements positioned apart from each other with only a spacethere-between and no other components may be referred to as such, in atleast one example. As yet another example, elements shown above/belowone another, at opposite sides to one another, or to the left/right ofone another may be referred to as such, relative to one another.Further, as shown in the figures, a topmost element or point of elementmay be referred to as a “top” of the component and a bottommost elementor point of the element may be referred to as a “bottom” of thecomponent, in at least one example. As used herein, top/bottom,upper/lower, above/below, may be relative to a vertical axis of thefigures and used to describe positioning of elements of the figuresrelative to one another. As such, elements shown above other elementsare positioned vertically above the other elements, in one example. Asyet another example, shapes of the elements depicted within the figuresmay be referred to as having those shapes (e.g., such as being circular,straight, planar, curved, rounded, chamfered, angled, or the like).Additionally, elements co-axial with one another may be referred to assuch, in one example. Further, elements shown intersecting one anothermay be referred to as intersecting elements or intersecting one another,in at least one example. Further still, an element shown within anotherelement or shown outside of another element may be referred as such, inone example. In other examples, elements offset from one another may bereferred to as such. As used herein, the term “substantially” isconstrued to mean plus or minus five percent of the range unlessotherwise specified.

The invention will be further described in the following paragraphs. Inone aspect, a hydraulic suspension system is provided that comprises: afirst manifold including a piston-side interface and a rod-sideinterface fluidically coupled to a piston chamber and a rod chamber,respectively, for each of a first hydraulic cylinder and a secondhydraulic cylinder; wherein the first manifold includes: a firstelectrically activated valve fluidically coupled to the piston-sideinterfaces, a first damping device, and a second damping device; whereinthe first electrically activated valve is configured to lock and unlockvertical motion of the first and second hydraulic cylinders; and whereinwhile vertical motion of the first and second hydraulic cylinders islocked, the first electrically activated valve permits fluidiccommunication between the first and second hydraulic cylinders to permitfree roll motion in the hydraulic suspension system.

In another aspect, a method for operation of a hydraulic suspensionsystem is provided that comprises: locking vertical motion of a firsthydraulic cylinder and a second hydraulic cylinder by closing a firstelectrically activated valve positioned in a first manifold andfluidically coupled to a first piston chamber of the first hydrauliccylinder and a second piston chamber of the second hydraulic cylinder;wherein in the closed position the first electrically activated valvepermits fluid flow between the first piston chamber and the secondpiston chamber and restricts fluid flow to a first damping device and asecond damping device from the first and second hydraulic cylinders,respectively. In one example, the method may further comprise unlockingthe vertical motion of the first and second hydraulic cylinders byopening the first electrically activated valve. In another example, themethod may further comprise unlocking suspension roll motion by closingof a second electrically activated valve coupled to a plurality ofpiloted check valves and a load sensing (LS) line. Further, in oneexample, the method may further comprise opening a second electricallyactivated valve coupled to a load sensing line in the first manifoldwhile closing the first electrically activated valve to discharge fluidfrom one or more accumulators in the hydraulic suspension system.

In yet another aspect, a hydraulic suspension system is provided thatcomprises a manifold fluidically coupled to a piston chamber and a rodchamber of each of a first hydraulic cylinder and a second hydrauliccylinder; wherein the manifold includes: a first electrically activatedvalve fluidically coupled to the piston chambers of the first and secondhydraulic cylinders and a first damping device and a second dampingdevice; and a controller configured to: during a first operatingcondition, lock vertical motion of the first and second cylinders byclosing the first electrically activated valve; wherein while verticalmotion of the first and second hydraulic cylinders is locked, fluidiccommunication between the first and second hydraulic cylinders ispermitted.

In any of the aspects or combinations of the aspects, the firstelectrically activated valve may be closed via energization of the firstelectrically activated valve.

In any of the aspects or combinations of the aspects, energizing thefirst electrically activated valve may close the first electricallyactivated valve to lock the vertical motion and de-energizing the firstelectrically activated valve may open the first electrically activatedvalve to unlock the vertical motion.

In any of the aspects or combinations of the aspects, closing the firstelectrically activated valve may activate a bridge connection and thebridge connection may fluidically couple the piston chambers of thefirst and second hydraulic cylinders and may restrict fluid flow to thefirst and second damping devices from the piston chambers.

In any of the aspects or combinations of the aspects, the bridgeconnection may be configured to: allow free roll movement in thesuspension system independent of a plurality of check valves in themanifold; and stabilize pressure in the piston chambers of the first andsecond hydraulic cylinders after transients between the piston chambersof the first and second hydraulic cylinders and a plurality ofaccumulators fluidically coupled to the first and second dampingdevices.

In any of the aspects or combinations of the aspects, while the verticalmotion in the first and second hydraulic cylinders is unlocked by thefirst electrically activated valve, the first damping device may be influidic communication with the first hydraulic cylinder and the seconddamping device may be in fluidic communication with the second hydrauliccylinder.

In any of the aspects or combinations of the aspects, the hydraulicsuspension system may further comprise a plurality of piloted checkvalves fluidically coupled to the piston-side interfaces and therod-side interfaces of the first manifold.

In any of the aspects or combinations of the aspects, the plurality ofpiloted check valves may be fluidically coupled to an LS component via asecond electrically activated valve.

In any of the aspects or combinations of the aspects, the hydraulicsuspension system may further comprise a leveling manifold fluidicallycoupled to the first manifold, wherein when leveling operation in theleveling manifold is active, the plurality of piloted check valves mayunlock suspension roll motion to balance cylinder leveling independentlyof a status of at least one electrically activated piloting controlvalve in the first manifold.

In any of the aspects or combinations of the aspects, the first andsecond hydraulic cylinders may be fluidically coupled to an independentfront suspension assembly.

In any of the aspects or combinations of the aspects, the firstelectrically activated valve may be closed via energization of the firstelectrically activated valve.

In any of the aspects or combinations of the aspects, the secondelectrically activated valve may be closed via energization.

In any of the aspects or combinations of the aspects, the secondelectrically activated valve may be closed via energization.

In any of the aspects or combinations of the aspects, the suspensionroll motion may be unlocked responsive to locking the vertical motion ofthe first and second hydraulic cylinders.

In any of the aspects or combinations of the aspects, the suspensionroll motion may be unlocked responsive to initiating leveling operationin a leveling manifold in fluidic communication with the first manifold.

In any of the aspects or combinations of the aspects, the controller maybe configured to unlock the vertical motion of the first and secondcylinders by opening the first electrically activated valve.

In any of the aspects or combinations of the aspects, the hydraulicsuspension system may further comprise a plurality of piloted checkvalves coupled to the piston chambers of the first and second hydrauliccylinders and the rod chambers of the first and second hydrauliccylinders; wherein the plurality of piloted check valves may be coupledto a load sensing (LS) line via a second electrically activated valve;and wherein the controller may be configured to unlock suspension rollmotion by closing the second electrically activated valve.

In any of the aspects or combinations of the aspects, the firstelectrically activated valve may connect the first damping device to thesecond damping device via a bridge connection when the firstelectrically activated valve is closed and locking the vertical motionof the first and second hydraulic cylinders; and the bridge connectionmay stabilize pressure in the piston chambers of the first and secondhydraulic cylinders after transients between the piston chambers and aplurality of accumulators fluidically coupled to the first and seconddamping devices.

In any of the aspects or combinations of the aspects, the hydraulicsuspension system may further comprise a leveling manifold coupled tothe first manifold via a tank line and a pressure source line andwherein the leveling manifold may include a plurality of valvesconfigured to independently adjust pressure in the first and secondhydraulic cylinders independent from position adjustment of the firstand second hydraulic cylinders.

In another representation, an independent suspension arrangement in avehicle is provided that comprises a central manifold including a valvein selective fluidic communication with piston and rod sides of eachcylinder in a pair of double acting hydraulic cylinders; wherein thevalve operates in a locked state in which the valve routes fluid betweenthe pair of double acting hydraulic cylinders; and wherein the valveoperates in an unlocked state in which the valve routes fluid betweenthe pair of double acting hydraulic cylinders and a pair ofaccumulators.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example, and notlimitation. It will be apparent to persons skilled in the relevant artsthat the disclosed subject matter may be embodied in other specificforms without departing from the spirit of the subject matter. Theembodiments described above are therefore to be considered in allrespects as illustrative, not restrictive.

Note that the example control and estimation routines included hereincan be used with various suspension system configurations. The controlmethods and routines disclosed herein may be stored as executableinstructions in non-transitory memory and may be carried out by thecontrol system including the controller in combination with the varioussensors, actuators, and other vehicle hardware. Further, portions of themethods may be physical actions taken to alter a state of a device. Thespecific routines described herein may represent one or more of anynumber of processing strategies. As such, various actions, operations,and/or functions illustrated may be performed in the sequenceillustrated, in parallel, or in some cases omitted. Likewise, the orderof processing is not necessarily required to achieve the features andadvantages of the example examples described herein, but is provided forease of illustration and description. One or more of the illustratedactions, operations and/or functions may be repeatedly performeddepending on the particular strategy being used. Further, the describedactions, operations and/or functions may graphically represent code tobe programmed into non-transitory memory of the computer readablestorage medium in the vehicle control system, where the describedactions are carried out by executing the instructions in a systemincluding the various hardware components in combination with theelectronic controller. One or more of the method steps described hereinmay be omitted if desired.

It will be appreciated that the configurations and routines disclosedherein are exemplary in nature, and that these specific examples are notto be considered in a limiting sense, because numerous variations arepossible. For example, the above technology may be applied to hydraulicsuspension systems with different configurations and in a vehicle with avariety of propulsion sources such as motors, engines, combinationsthereof, etc. The subject matter of the present disclosure includes allnovel and non-obvious combinations and sub-combinations of the varioussystems and configurations, and other features, functions, and/orproperties disclosed herein.

The following claims particularly point out certain combinations andsub-combinations regarded as novel and non-obvious. These claims mayrefer to “an” element or “a first” element or the equivalent thereof.Such claims should be understood to include incorporation of one or moresuch elements, neither requiring nor excluding two or more suchelements. Other combinations and sub-combinations of the disclosedfeatures, functions, elements, and/or properties may be claimed throughamendment of the present claims or through presentation of new claims inthis or a related application. Such claims, whether broader, narrower,equal, or different in scope to the original claims, also are regardedas included within the subject matter of the present disclosure.

The invention claimed is:
 1. A hydraulic suspension system, comprising:a first manifold including a piston-side interface and a rod-sideinterface fluidically coupled to a piston chamber and a rod chamber,respectively, for each of a first hydraulic cylinder and a secondhydraulic cylinder; wherein the first manifold includes: a firstelectrically activated valve fluidically coupled to the piston-sideinterfaces, a first damping device, and a second damping device; whereinthe first electrically activated valve is configured to lock and unlockvertical motion of the first and second hydraulic cylinders; and whereinwhile vertical motion of the first and second hydraulic cylinders islocked, the first electrically activated valve permits fluidiccommunication between the first and second hydraulic cylinders to permitfree roll movement in the hydraulic suspension system independent of aplurality of check valves in the first manifold.
 2. The hydraulicsuspension system of claim 1, wherein energizing the first electricallyactivated valve closes the first electrically activated valve to lockthe vertical motion and de-energizing the first electrically activatedvalve opens the first electrically activated valve to unlock thevertical motion.
 3. The hydraulic suspension system of claim 2, whereinclosing the first electrically activated valve activates a bridgeconnection and wherein the bridge connection fluidically couples thepiston chambers of the first and second hydraulic cylinders andrestricts fluid flow to the first and second damping devices from thepiston chambers.
 4. The hydraulic suspension system of claim 3, whereinthe bridge connection is configured to: allow the free roll movement inthe suspension system independent of the plurality of check valves inthe first manifold; and stabilize pressure in the piston chambers of thefirst and second hydraulic cylinders after transients between the pistonchambers of the first and second hydraulic cylinders and a plurality ofaccumulators fluidically coupled to the first and second dampingdevices.
 5. The hydraulic suspension system of claim 1, wherein whilethe vertical motion in the first and second hydraulic cylinders isunlocked by the first electrically activated valve, the first dampingdevice is in fluidic communication with the first hydraulic cylinder andthe second damping device is in fluidic communication with the secondhydraulic cylinder.
 6. The hydraulic suspension system of claim 1,further comprising a plurality of piloted check valves fluidicallycoupled to the piston-side interfaces and the rod-side interfaces of thefirst manifold.
 7. The hydraulic suspension system of claim 6, whereinthe plurality of piloted check valves are fluidically coupled to a loadsensing (LS) component via a second electrically activated valve.
 8. Thehydraulic suspension system of claim 6, further comprising a levelingmanifold fluidically coupled to the first manifold, wherein whenleveling operation in the leveling manifold is active, the plurality ofpiloted check valves unlock suspension roll motion to balance cylinderleveling independently of a status of at least one electricallyactivated piloting control valve in the first manifold.
 9. The hydraulicsuspension system of claim 1, wherein the first and second hydrauliccylinders are fluidically coupled to an independent front suspensionassembly.